This invention relates to electrical connectors, and more particularly to a high density bi-pin lamp socket for ensuring adequate dielectric withstanding voltage (DWV) between the terminals.
Presently, a great number of high density bi-pin lamps, wherein the contact pins are very close together, are employed in the manufacture of commercial aircraft. In a typical airliner, they are used to illuminate the No Smoking/Fasten Seat Belt signs, the floor proximity lighting fixtures, and other lighting applications. The problem is that Government specifications require such lamp sockets to withstand 1000 VRMS dielectric voltage between the socket terminals, tested with the lamp removed. Because the contacts are so closely spaced, this standard is extremely difficult to meet.
Referring now to the prior art figures (FIGS. 1 and 2), two alternate methods for installing the current state of the art lamps are shown. In FIG. 2, the lamp 10 is inserted into the receptacle 12 by inserting contact pins 14 and 16 into corresponding terminals 18 and 20 within the receptacle 12. The dielectric 22 separating and insulating the terminals 18 and 20 is theoretically adequate to provide the required dielectric withstanding voltage, but in actuality fails to do so in application. A prime reason for this failure is that the terminal sockets are soldered to a pair of printed circuit boards 23a, 23b (anode and cathode) through the dielectric 22 at joints 24, and these solder joints inevitably flow together, causing shorting across the spacing between the terminals. To combat this problem, the common currently employed installation method, as shown in FIG. 1, is to increase the spacing between the terminals 18 and 20 within the dielectric 12, such that there is a greater amount of dielectric insulation between them. To enable the more narrowly spaced lamp contact pins 14, 16 to be inserted into the more widely spaced terminal sockets, the pins are pulled and formed such that they transition from the narrow spacing at their proximal ends to a wider spacing equivalent to that of the terminals 18, 20 at their distal ends. However, this forming proces, typically performed by the lamp installers, is labor intensive and frequently causes cracking of the lamps procelain core, thereby shortening the life of the lamp.
What is needed, therefore, is an improved device which allows the contact terminals to be widely spaced as shown in FIG. 1 without requiring the contact pins of the lamp to be physically spread apart, thereby greatly decreasing the labor required to install the lamps while further increasing the longevity of the lamps as well.